The two shows both launch on March 24, with The Voice originally due to air from 7.15pm-8.30pm while BGT was due to start at 7.45pm and finish at 9pm â resulting in a hefty overlap between the two programmes.

The BBC, who spent £25million acquiring the rights to the format, have repeatedly stated that they wanted to avoid the clash and have moved the start time to 7pm in an effort to reduce the overlap.

BBC1 controller Danny Cohen had previously insisted the BBC would avoid a scheduling clash, saying: ‘We won’t want to be going head to head with BGT, that is not our intention.’

The BBC did attempt to move The Voice and avoid a clash (Picture: PA)

But ITV â who accused the BBC of ‘parking its tanks on our lawn’ after the clash was first announced â has apparently chosen to declare war on its prime-time rival, reportedly deciding to move earlier too.

Today is the last opportunity for broadcasters to change the television schedule, so it seems likely that viewers will be forced to choose between the two shows.

BGT boss Simon Cowell seems more than up for a fight, saying recently: ‘I like the competition. You want to kill the opposition.’

Alesha Dixon hits a Cuban bar (Picture: ITV/PA)

David Walliams films a period drama (Picture: ITV/PA)

The news comes as Britain’s Got Talent unveiled a new trailer to promote the show, featuring the four judges coming together to complete a mission ‘for Queen and country’.

The spoof promo features the judges supposedly going about their daily lives â David Walliams roams the street on the set of a period drama, Simon Cowell sits in a high-rise office with a patriotic teapot, Amanda Holden is backstage at an old theatre while Alesha Dixon is dancing at a Cuban bar.

Amanda Holden dons a dazzling gown backstage at an old theatre (Picture: ITV/PA)

The judges then receive a mystery call summoning them to a secret mission, with the four donning their best outfits as they come together for the first time.

The advert, which a show spokesman said was designed to ‘reflect a national mood of patriotism’ ahead of the Diamond Jubille and London 2012 Olympics, will debut tonight during Chelsea’s Champions League match against Napoli.